class Sum {
public:
    Sum() {
        _ret += _i;
        _i++;
    }
    static int Getret() {
        return _ret;
    }

private:
    static int _ret;
    static int _i;
};

int Sum::_ret = 0;
int Sum::_i = 1;

class Solution {
public:
    int Sum_Solution(int n) {
        Sum a[n];
        return Sum::Getret();
    }
};